In order to connect one optical fibre to another, the fibres are equipped with connectors at their ends. There are many types of such connectors, the most commonly used in North American telecommunications applications being AT&T's (American Telephone and Telegraph) ST-type connector, and NTT's (Nippon Telegraph and Telephone) FC-type connector. Two fibres which are to be connected are equipped with the same type of connector (FC or ST), and these connectors are each connected to an intermediate coupling receptacle. Both these types of connectors rely on a ferrule to achieve precise fibre alignment, but they employ different and incompatible latching mechanisms. The ST-type connector relies on a 1/4 turn bayonet (spring loaded twist and lock) coupling mechanism, and the FC-type connector relies on a threaded coupling mechanism. In order to interconnect two fibres which are terminated with different connector types, for example an FC terminated fibre and an ST terminated fibre, special adaptors are required. Using such special adaptors is not convenient and introduces extra loss in the connection.
In addition to the need to facilitate connections between two optical fibres, there is also the need to facilitate the connection between a fibre and an active device such as a detector, laser or LED (light emitting diode) mounted in a receptacle mount. Typically, active devices have receptacle mounts which are capable of receiving one of ST or FC-terminated fibres but not both. Thus, to connect an FC terminated fibre to an active device having an ST-type receptacle mount, again special adaptors are required.
The most commonly used fibre connectors in local area communications include the SC-type connector and the above identified ST-type connector. Again, these connectors use different and incompatible latching mechanisms with the ST-type connector relying on the above identified 1/4 turn bayonet coupling mechanism, and the SC-type connector relying on a push-pull coupling mechanism.